Diffusing apparatus



Sept. 11,1923. HAEZMQ \N. C. GRAHAM DIFFUSION APPARATUS Ofiginal FiledDec. 2, 191a gnventoz M zf-W.

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Patented Sept, 11, 1923.

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"rarer era' WALTON C. GRAHAM, OF-IDENVER, COLORADO.

DIFFUSING APPARATUS.

Original application filed December 2, 1918, Serial No.2,64,97{l.Divided and this application filed September 8, 1823.

T0 (ZZZ whom it may concern:

Be it known that I, VVALTON C. GRAHAM, a citizen of the United States,residing at Den ver, in the county of Denver and State of Colorado, haveinvented new and useful 1m.- provements in Diffusion Apparatus, of whichthe following is a specification.

This invention relates to the art of. treating solids with liquids andparticularly to apparatus for extracting soluble matters from masses ofshredded or finely divided materials. The invention has special utilitywhen employed in the extraction of saccharine matter from finely dividedsugar beets or cossettes, but is by no means limited to such use.

In the art of extracting soluble. matter from materials, and especiallyin the beet sugar industry, it is, as is well known, of the utmostimportance to keep the juices as concentrate as possible, so as toreduce to a minimum the volume of liquid to be evaporated. lVith this inmind, I have devised a process of and means for confining the materialto be treated in a compact mass, and for continuously treating the sameunder high pressure.

The process claims are presented in my Patent 1,437,801, December 5,1922, from the application of which the apparatus claims have beendivided.

The invent-ion accordingly comprises apparatus for conducting acontinuous method of the kind described in which the material is carriedalong by a stream of liquid, and at the same time, is acted upon byastream moving geuerally in the opposite direction, the material beingheld in such a way as to be brought into intimate and uniform contact,under pressure, with the treatingliquid, and prevented from packing. Theapparatus includes improved means for carrying out the above process, inwhich the rate of flow, temperature, pressure, degree of exhaustion,extent of concentration, etc., can be readily controlled, and in whichthe re sults can be accomplished with a minimum of labor. My improvedapparatus is moreover, exceptionally compact, simple. in constructionand operation. and of comparatively low first cost.

In order that the invention may be readily understood, reference is hadto the accompanying drawing,

forming part of, this Serial No. 586,846.

specification and which illustrates-more or less diagrammatically theapparatus constructed and arranged in accordance with theinvention.

Referring to the drawingin detail, A. dee ignates a hopper into, whichthe sliced beets or cossettes are fed. This hopper has a conical bottomB and a lining C of Woven wire or the like, spaced from the walls of thehopper as shown. A stirrer D is arranged near the bottom of the hopperand is mounted on a vertical shaft driven by suitable gearing from abelt pulley or the like E.

From the bottom of the hopper extends aconduit F to the intake side ofthe centrifugal or other pump P and from the discharge side of this pumpextends a pipe or conduit G to the treating chamber H, This chamber ispreferably cylindrical and is of comparatively great length or heightrelative to its diameter. The chamber is aif ranged vertically and thepipe G communicates with the bottom thereof. Inside of the chamber H atthe top and bottom thereof are cone shaped foraminous partitions J and Krespectively; the large ends of these coneshaped partitions facingtoward the middle of the chamber. Spaces L and M respectively are formedbelow and above the foraminous partitions J and as shown. From the spaceL extends a pipe or conduit N back to the hopper A with which itcommunicates near its upperend. A discharge pipe 0 also extends from thehopper A at substantially the same level as the pipe N.

A pipe Q communicates-with the upper space M of the treating chamber andis controlled by means of a valveV,

Extending upwardly from the center of the. chamber H and partition K isa discharge pipe R controlled by a valve U. The mouthof this pipe may,also be controlled by means of an adjustable bell S,- as shown in thedrawing. I I

Suitable heating meansT is interposed in the pipe Q and other heatingmeans T and T are interposed in the pipe N, a heating medium such assteam being supplied to the heaters by means of a pipe W, and pivotedvalves, or the like, Z ,.Z and Z being employed to govern the flow of.liquid through each of said heaters. By this means any or all of theheaters may be used,..a's.desired, and the temperature of the liquidsthus controlled. Valves X and Y are interposed in the pipes G and Nrespectively for, controlling the flow of material therethrough.

To start the apparatus in operation, the hopper A is first filled to theoverflow point 0, either with fresh or saturated solvent, and the valvesX and Y being open, the treating chamber H will likewise be filled withthe said solvent to a height determined by the position of the overfiowO, as will also the connecting lines G and N and the heaters T T L Thefinely divided material from which the soluble matter is to be extractedis'now introduced into the top of the hopper A, and'within the screenenclosure C, the pump and stirrer are'started and the mixture of liquidand solids is forced through the pipe G into the lower portion of thechamber H,

Here the solid material collects above the screen, while the liquidpasses through the screen into the space L and back by means of the pipeN, through the heaters to the hopper A. This is accomplished by gravity,

I as the introduction of the additional liquid carrying the solids.displaces an equal amount of that within the chamber H.

1 This operation is continued until the entire interior space in thechamber H between the screen or partitions J and K is filled with acompact mass of material to be treated, such material being compressedagainst the upper partition by the action. of the pump P, and the liquidmeanwhile being continuouslyreturnedtothe hopper A;

Alter the chamber H is filled, as described, the valves X and Y aretemporarily closed, and the pump stopped.

Fresh solvent or treating liquid, such as water, which has been heatedby passage through the heater T is now admitted through the pip-e Q, byopening the valve V. This solvent enters the space M, where itpercolates downward throughthe small in terstitial spaces of the compactmass of material; the displaced air rises as the space is occupied bythe liquid and passes out at the top throughthe pipe R, until finallythe interstitial spaces within the chamber H are completely filled withthe liquid;

Next-the valve Y is opened, and a flow of liquid takes place from'thetop of the chann her to the bottom, and by means ofthe pipe N into thehopper A, which being full, will cause the overflow of an equal amountof liquid through the pipe. 0. Thisflow of solvent through the chamberll should be continued until the soluble matter in the ma terialadjacent to the upper conical screen K is'eicliaustcd to the desiredextent.

Theinitial step of charging the chamliwer H and exhausting the upperlayers of material having been accomplished, the system is in readinessto begin the continuous open ation; To do this, the introduction of thefinely divided material to be treated into the hopper A is resumed, andcarried on uninterruptedly, the valvew is opened and the pump andstirrer set in motion with the result that, valve Y being also open,further amounts of a mixture of liquids and solidsare. continuouslypassed into the bottom of the treating chamber H, Where the solids areretained above the screen a s-before, and the liquid returns by gravitythroughthe pipe N by way of the heaters to the hopper A. Each incrementof solids obviously displaces a corresponding quantity of the exhaustedmaterial or pulp at the top of the chamber H, which is forced throughpartly open bell S and the pipe" R and out of the apparatus, the valvebeing open.

The introduction of fresh hot solvent through pipe Q is continued, andthis progressively displaces the charged solvent, which escapes'throughpipe N, and eventually overflows at O.

The dissolving'o'f the soluble matters is accomplished' by the passageof the liquid introduced. throughthe pipe Q, and at the same time, theexhausted material is discharged through the pipe R.

The solvent in its downward path comes in contact with material carryingincreasingly greater amounts of soluble matter, while the solids inpassing upward come in contact with solvent of continually decreasedcontent of solubles, the effect of the proce durej'being to exhaust thesolids of soluble matter and at the same time obtain the greatestconcentration of such soluble matter in the solvent.

As the well saturated solvent passes out oi the chamber H through theforaniinous partition J by the line N, through the heater CP -T it comesfinally in contact with the absolutely fresh material to be treated, inthe hopper A, and its interior screened en closure G, where by reasonofits increased temperature and the greater content of soluble matter inthefresh material, a further extraction of such soluble matter takesplace to the utmost possible extent.

In practice the relative amounts oi solvent, and solids to he treatedwill be maintained in the h'opper in such a proportion that the freshmaterial dropping into the hopper will be imn'iediately heated to thedegree which is considered necessary for proper sterilization.

The forces of ditl'usion will have reached very close to an equilibriumbetween the concentrated solvent and the solids within the hopper, sothat the fact that a portion of this liquid is used as a carrying mediumto convey the solids into the treating chamber H will have very littlefurther elfect as to dissolving solubles.

. That portion of the concentrated solvent so used will mix in thebottom portion of llll) the chamber H and in the space L with the mainbody of the solvent, and pass with it back to the hopper A and out.

The action in using a portion oi the concentrated solvent as a carryirnmedium for the solids to be treated is that or temporarily borrowing aportion oi. the liquid at one point and returning it at another, and asfar as the difi'usion process is concerned the effeet will be little ifany under proper con ditions, and. is an entirely independent operationoutside the cycle of dii'iusion.

Taking the total amount of solvent as 100, ii 20 parts of it becontinually in use as a carrying medium, the effect will be that i120parts of solvent will pass through the pipe N and the heaters T -T foreach 1.00 parts of solvent passing through the chamber H, and it willthus assist in carrying greater amounts of heat to the hopper A.

It is obvious that the length oif treatment or the degree of exhaustionof the material is dependent upon the height of the chamber H, and thatthe amount oi material which may be treated, or the capacity isdependent upon the diameter oi the chamber H.

Further the concentration of the solvent will be proportional. to theamount of solvent admitted through the pipe Q, as compared with theamount oi the solids to be treated or the soluble matter to bedissolved.

The extent oi the packing or the pressure maintained within the chamberH. over and above the hydrostatic pressure of the column will becontrolled by the extent oi? the open-- ing oi the valve U. and theposition of the adjustable bell S.

This process may be applied to removing soluble matter irom materialwhich is oi such a nature. that when finely divided to the extentrequired for the operation oi the forces of diffusion or osmosis. thesame will not pack so tightly but that there remain uniformlydistributed interstitial spaces throughout the mass.

()winp to the manner in which the material is deposited within thetreating' cylinder it must be necessarily unii o nily distributed; andany tendency toward inequality will be automatically corrected by theilow oi the conveyingliquid. Vihile thereiore. the treating liquid canfreely percolate through the mass the onstant upwa d move-- ment of suchmass will counteract any tendency toward plugging or channeling.

It will be observed that while the mass of material in the treatingcylinder H works gradually upward. the treating or solvent liquid movesdownward through such mass. giving rise to the peculiar result thatalthough the material is conveyed by means oi a current or" liquid. itmoves in a direction opposite to the direction oi iiow of the solventliquid. thus employing the principle oi counter-currents.

Having thus described my invention, what I claim as new and desire tosecure by Let ters Patent. is:.

l. Diii usion apparatus comprising a tank, a hopper. a foraminouspartition in said hopper dividing the latter into two conipartmentsconstituting a first and a second compartment, a pipe communicating withsaid first compartmentand the interior oi said tank, propelling meansfor passing material through said pipe toward said tank, a second pipeextending from said tank to said second compartment, a foraminous screenin said tank extending across said tank between said first and saidsecond pipe openings, an overflow pipe leading -from said secondcompartment and. near the top of said hopper and at a level above thelevel of the bottom level of said tank, and a third pipe leading); intosaid tank and constitutingmeans for supplying liquid to said tank andhopper and maintaining the liquid level up to that of said overflowpipe.

2. Dii'l'usion apparatus comprising a closed vertical tank, a pair oifixed foraminous partitions extending; across the tank and located oneadjacent each end thereof, a conduit in ported communication with theinterior of said tank between said partitions and constituting means fordelivering material to be treated into the space between the partitions,and pipe means opening into said tank at a point above said upperpartition and constituting liquid inlet means, and a. discharge pipeleading from said tank at a point below the lower partition.

Diffusion apparatus comprising a closed vertical tank. two fixedtoraminous partitions one positioned adjacent each end oi said tank andextending; across the same. a conduit in ported communication with theinterior oi said tank between said partitions and constituting;materials above the lower partition, pipe means opening into said tankat a point above said upper partition and, constitutingliquid intakemeans. means iior admitting treating liquid above the upper partition.and, means iior wihdrawinp liquids if'rom the tank at a point below thelower partition.

4t. Diilusion apparatus comprising a closed vertical tank having; aninverted conical, toraminous partition at its lower end and a Secondconical ioraminous partition at its upper end. means For delivering amixture of liquid and solid materials into the lower end oi the lowerpartition. a dis charge pipe for solid matter communicating with theupper end of the upper partition, and means fo withdrawing liquid "Froma point below the lower partition.

5. Diffusion apparatus comprising a closed vertical cylinder having acone shaped toraminons partition at each end thereof,

the large ends of said partitions both facing toward the center, adelivery pipe entering the lower end of the cylinder and communieatingwith the space inside of the rorresponding partition, a discharge pipeextending from the upper end of the cylinder and communicating with thespace inside the corresponding partltion, means for delivering liquid tothe upper end of the cylinder outside of and above the upper partitionand 10 means for discharging liquid from the lower end of the cylinderat a point outside of and below the lower partition.

r In testimony whereof I affix my signature.

WALTON C. GRAHAM.

